1. Field of the Invention
The present invention relates to a side airbag system, which controls the deployment of the side airbag.
2. Description of Relevant Art
As an example of the method for protecting the occupant against injury in the event of collision with another vehicle, the method of deploying the airbag instantly in order to protect the occupant of a vehicle has been known. Among these kinds of airbags, the side airbag to be deployed sideward with respect to the occupant in order to protect the occupant has been widely spread.
In these kinds of side airbags, conventionally, the deployment of the airbag is controlled based on various methods. Among these kinds of the control methods, the method, in which the deployment of the airbag is determined after checking whether or not the occupant is sitting on the seat, has been known. As an example of this method, the side airbag apparatus disclosed in Japanese unexamined patent publication 2000-85524 can be cited.
In this Japanese unexamined patent publication 2000-85524, the presence of the occupant on the seat is checked using an electric capacitance sensor. In this conventional method, since the electric capacitance sensor is disposed at an upper part of the seat back of the seat, the presence of the occupant cannot accurately be detected when the occupant is sitting at the side edge of the seat (the occupant is sitting away from the electric capacitance sensor). In this case, it is judged that there is no occupant on the seat.
That is, the presence of the occupant can not be detected unless the occupant is sitting on the seat in an adequate posture.
In this conventional method, however, the presence of the occupant on the seat can be detected by the electric capacitance sensor irrespective of the size of the occupant's physique as long as the occupant is sitting on the seat in an adequate posture.
In this conventional method, additionally, a presence sensor, which simply detects the presence of the occupant, is used in order to prevent the occurrence of detection error, which is caused by the fluctuation of the humidity in the air, of the electric capacitance sensor. In this conventional method adopting the presence sensor, the detection value obtained by the electric capacitance sensor is regularly initialized if the occupant sensor detects the presence of the occupant on the seat for many hours. Thereby, since the influence of the fluctuation of the humidity can be reduced, the occurrence of detection error can be minimized even if the fluctuation of the humidity in the air occurs.
In this conventional method adopting the initializing methods, the detection of the occupant in response to constantly changing situations has been difficult
For the reasons mentioned above, the side airbag system, which can accurately detect the presence of the occupant irrespective of the change of ambient surroundings, and which can control the deployment of the side airbag after checking whether or not the occupant is sitting on the seat, has been required.